Production of a catalyst from clay



Patented et. 5, 1952 UNITED?" STATES OFF-"ICE PRODUCTION -'0F- ACATALYST FROM- CLAY,

George AlexandenMills, Ridley Park} Pa; assignol to. iHoudr-y; Process,Corporation; Wilmingtona D'l.," a corporation .ofiDelawaize No Di 'awingfi Application Ma'y'283i1 4' Scria'liNo. 1372;917

'4 Claims. (01. 2521-4511) The present invention relatestothepreparationtof adsorptivecontact masses and .iswespe z ciallycconcernedl withithev preparation of -su'ch tonites. area familiarexample, are conventionally: activated-Slay. acidmtreatment to producet-active -v con-tact, masses :of good adsorbent properties, useful in;,deco lorizing -:.and ;otherrelations. Such acid-activated clays inmany instances. also displayucatalytio. activity R of, sufiicientlyhigh; level V andrdesired selectivity, such that they havc'foundextensiveicommercial use vas catalysts .in .thydrocarbonwonversionprocessesh. There are, how-- even-many commons-and abundant clays; forex-, ample kaolin clays, which do. not respond to conventional; acidactivation to produce contact. massesoi required adsorptivity Theseclays,,as

20. good adsorptivi'ty in the acid-treated or even raw- Staten such as".fullerjs earth, do; not respond to conventional l acid-activation: to.furnish catalysts .1 of required selectivity and desired high leve1= ofwellaasvcothers which i on. the. other v hand show activity for use inhydrocarbon conversion processes. I have found that clays which do notsufficiently respond:tto. .acid treatment, including clays.ofi..-the-kaolin type, may beactivated by novel methodsvas:hereinafterdescribed; and cracking catalystssofgood activity and :desiredselectivity:

thereby obtained; V

The term activity as herein employedwithjl respect to catalysts, hasreference to the relative efllciency of "the catalyst when employed inhydrocarbon cracking operationsof producing---gaso linef--from--higher-boiling petroleumproducts.

The relative efficiency -orindex 'of activity of a catalystiorfl-use-inhydrocarbon crackingand 'ree forming operations can 'be determinedanticompaged by-af test of its performance-in catalytic cracking-of1astandardized "petroleum fraction unde i; selected cooperating.conditions. One 7 such testifi 'con' mon'use is'that known asthe .CAT AImethod' 'described in Laboratory Method 'of,De-. teri'nining the.Activity. of Cracking Catalysts,.. bys

J llAlexander and G. vShimp National Pe-. trole'um News, August-2,v1944,atiprR 537. In acto ,-.volu mei of. .icatalyst-vperi, hour), duringiaten= minuteioperating period. a Theliquid products are fractionatedqandtheivolume roof .4105? end .--point i motor, gasoline-.measuredattic-activity oftthecataa;

lys-t =istdenoteddn terms ofv the; =percentage oft. the

gasoline yield on thewolumeaofi gas oil charged;

The'weight p'er cent oiicoke;deposited,;the= -weigl1t, per cent eofmormally :gaseous products. oformedi. and specific gravityireferredito.air)v oi such gastric;

arealso-measured;

In its -tb-i'oadvaspect =the-.-present.inv.ention com-i,

prises tl ie activation:ofxclayaof norma1Lv,,1ow -i activityaandwhichis'notbnought .to-highactivity;--.level-='by-conventionalzacidfltreating.i; I-have foundti-iatsibyr'subglectingsuch: clays $0.; a tbasic. treat fl mcnti theicapacityeof; the. clayitotincorporate andretain;an;activatingsicomponent is 1iincreased-.,.-solthatiby.:impregnatingathectreated tclay withi such o. activating;component :orazwithj an: agent; reactive tc form .such-tcomponentgthereinhthwactivity ;of then clay sisismate'rially :imDJIQVEd-L 7 Thus; in ,ace cordancewwith :a preferred; embodiment, a rawclay-:-of the;kaolin type =.is initially acid, treated washed,adridfiformeddnto pellets; and subjected to- -heattreatmentwTheheatetreated pellets are soaked in -a:diluteasolutiomofi;.sodiumtihydroxide r for suflicient time :to increase the. sodiumcontentthereof andaftenwashina with Water the, pellets: are 'furthertreatedwith asolutionof an ialumie num' sal-t such 'as aluminum sulfate;eiiFectinguree placement ofthe sodium: by 'alu'niinum; thereby: 1

incorporating alumina-in the pellets; Acidtreatment ofl the 'cla'y" isnot alwa'yyrequired-p sinceraw as well as acid-treated clays:

which are below desired activity may -;bebrought 1 to' high activitylevel-by?- thei'incorporationof alumina as described,"-and even'rawclaysof poor activity considerahly:improved thereby. In -hy--drocarbonicrackingand reforming operationsgthe ga-soline yield, obtainedis' of considerable -sig nificance 'and accordin'gly the more important1 catalysts produced in "accordance with the inven tionaregthoseof*highactivityf=leveL for instance *thosegivi'ng yields 0f 30%or more gasoline astested "by -therdescribed-* CAT A"' method;

For th'e 'initialfacid treatnientof the raw clay if 'pra'cti'cedinineral acid of-moderateconcen 1 tration may bi used." Thus," aqueousacid 'solu-' tions ot the "usual concentrations gand propor tions "to"clay weight as are-employed inknowm activation of. "conventional acidactivatable clays. ma be, used; if desiredfjandi' preferably at an Ieievatedgte'mnerat re below the boilin poi t of the. acidisolution.vFoninstance, in .the, pref erred 1 treatment, .suIfuricMacid (is;employed ,of 5%, to.

60%,concentration{calculated{onethe iotalflwaterfl I contenttoi, shamanthe...quant ity, oi .acid on anav BBL-hydrous basis rangingfromaboutmwlo overt 0 3 parts of the dry clay, the acid treatment beingeffected at a temperature of about 200 F. Under these conditions thenecessary acid treatment can be accomplished in about 3 to 8 hours.

If the activating component is to be incorporated in pelleted clay, asis preferred, the acidtreated clay is formed into pellets of suitablesize in any known or desired manner, but preferably following apurification treatment such as washing to remove adhering acid, andwater-soluble materials. After draining the wash'water or filtering, theclay is dried and ground to powder. Pellets may be formed by compressingor stamping the dry powder to units of desired size and shape, but it ispreferred to first rewet the powder with a regulated quantity of waterto form a plastic mix and cast or extrude the wet mix. To assistextrusion, removable binders or volatile water-immiscible liquids suchas kerosene may be added. As an example of an extrusion operation, theclay powder is mixed with about an equal weight of water and the mixextruded in a macaroni machine through dies obtaining strands of 2 to 4mm. diameter, which are cut respectively to corresponding lengths. Theobtained pellets are then dried not too rapidly, which may be done inovens provided with forced aircirculation, so that the moisture contentis reduced to about or somewhat below. Such drying may be effected butis not restricted to temperatures in the order of 'l00250 F. requiring aperiod of several hours for the operation. The dried pellets are thensubjected to heat-treatment to drive 01f volatiles and to stabilize thepellets, which may be efiected at temperatures above 500 F. in air orother non-reactive gas to which small amounts of steam may be added. Asan example of a preferred heat-treatment, the pellets may be subjectedto calcination in air at 1050 F. for 2 hours,

By acid treatment as above described, acid activable clays, such asmontmorillonite clays of the sub-bentonite family, can be readily madeinto catalysts of fairly high activity level, but by such treatment ofthe typesof clay with which the inventionis concerned, such as kaolinclays, contact masses having a high level of catalytic activity aregenerally not obtained. The activity of clays of the latter class isimproved, in accordance with the invention, by treatments such ashereinafter described.

Heat-treated pellets produced from the kaolin clay by theabove-described or an analogous procedure, in accordance with thepreferred embodiment are soaked in dilute'sodium hydroxide solution toincrease the sodium content and thereby enhance the adsorptivity orreactivity of the pellet, in preparation for the subsequent step. Theconcentration of the sodium hydroxide employed should be below thatwhich will effect disintegration of thepellets under the treatingconditions employed and preferably insuflicient to dissolve anysubstantial portion of the silica or alumina components of the clay. Forexample, the treatment may be advantageously carried out in 4 to 10%sodium hydroxide solution at room temperature over a period of 8 or morehours, employing a quantity of liquid sufficient to cover the pellets.At the temperature and concentration indicated, the treatment with thesodium hydroxide solution may be prolonged over several days, ifdesired, without untoward effect, thereby increasing the quantity ofsodium incorporated; Extended treatment beyond about 35150 40 hoursgenerally serves no useful purpose.

, extruded to form 4 mm. cylindrical pellets.

The treated pellets are thereafter washed with water to free the same ofadhering or physically held sodium hydroxide and other soluble materials. The washed product is then treated with u an aluminum saltsolution in sufficient excess to assure reaction with or replacement ofall of the available sodium compound in the pellets. Thus, the pelletsat this stage may be treated with a 10 to 20% (by weight) solution ofaluminum sulfate -A12(SO4)3.18H2O, the treatment bein advantageouslyrepeated several times. As a result of the replacement of sodium byaluminum. alumina (as oxide or hydroxide) is incorporated in the pelletsapparently in complex combination with natural clay components. Afterwashing the pellets until free of sulfates (or other anions of thealuminum salt employed) in the wash water filtrate, the pellets aredried and preferably again heat treated and calcined as before or at adifierent selected temperature in the presence or absence of steam, tostabilize the same at desired activity level governed by the type ofpetroleum stock or conversion operation in which the same are to beused.

The aluminum salt solution used in the above process may beadvantageously obtained from the acid extract derived in the initialacid treatment of the raw clay. Since such extract, however, willcontain in addition to the aluminum salts of the acid, undesired metalsalts such as those of iron and in some instances titanium, it ispreferred to purify the extract to obtain a substantially pure aluminumsalt solution for use Y in the subsequent step of treating the pellet.Such purification may be effected by selective precipitation such as bytreatment with strong caustic solution to precipitate the iron (andother insoluble hydroxides) while retaining the aluminum in solution.Other methods of separat ing iron from aluminum solutions may beemployed, such as those described in my joint copending applicationSerial No. 666,179, filed April 30, 1946, issued November 29, 1949 as U.S. Patent 2,489,309.

Example I The clay employed for the several preparations of pellets inthis example was a kaolin from the region of Putnam County, Florida,known commercially as Edgar E. P. K. and having the followingcomposition on a dry C.) sandfree basis.

Ignition loss percent 12.9 S102 d0 46.6 A1203 d0 38.8 F6203 d0.. 1.0 CaOdo 0.44 MgO do 0.23 T102 d0 0.35 Alk. Metal (as oxides) do 0.52

(a) The raw clay was milled with 20% sulfuric acid, employing 0.55 partsof acid (anhydrous basis) to dry weight of clay, at 93 C. for eighthours. The acid was drained and the clay washed with water until thefiltrate tested free of S04 ions, after which the clay was dried, workedwith water to moldable consistency and The pellets were calcined for 2hours in air at 1050 F. (b) A portion of the calcined pellets from (a)above were placed in 6% sodium hydroxide solution for eight hours atroom temperature, then washed fifteen times with Warm water. Follow- .75

ing washing, the'pellets were treated 3 times with Jets each-time. fwithwateriuntil the .filtraite was S04 free,.dried calcined at 1050 F.for two hours .in air.

'. (1:) -3Fo r comparison, the raw ikaolin used .above was pelleted byextrusionf-without previous acid treatrr'ient and similarly treated withsolutions of sodium hydroxide and aluminum :sulfateandcalcindiasin-(b),and i (fi) Theguntreated raw kaolin merely pelleted andsimilarly calcined. 1

'Zlhe' pellets fromla), .(b), .(c) :and (.11) above, separately tested.in cracking of a light gas oil by th'e' CAT-A method above described,gave :th ne's'ult's tabulatedbelow:

The clay employed in the several preparations of pellets in this examplewas a kaolin obtained from the Eccles property in Putnam County, Floridawhich had the following composition by weight on an ignited basis(containing -20% sand):

SiOz percent 65.8 A1203 do 32.4 F8203 dO 1.4 CaO do 0.23 MgO do 0.21TiOz do 0.69

(a) The clay was acid treated by a procedure similar to that in ExampleIa above, using 30% sulfuric acid in a ratio of 0.60 (anhydrous basis)acid to dry weight of clay, the acid treatment being continued for fourhours at about 200 F. The acid treated clay was washed, dried, pelletedand calcined as in Example Ia above.

(b) A portion of the obtained pellets were treated with sodium hydroxidesolution and then with aluminum sulfate solution as in Example Ib, andsimilarly dried and calcined.

(c) For comparison, the raw Eccles kaolin was pelleted without previousacid treatment and similarly treated with a solution of sodium hydroxidefor 24 hours, washed and then treated with aluminum sulfate solution,followed by drying and calcining as in (b) above, and

(d) Theuntreated raw kaolin merely pelleted and similarly calcined.

The following results were obtained on testing samples of each of theabove pellets in catalytic cracking by the "CAT- method:

Example III (a) The same Eccles kaolin as employed in the precedingexample was pelleted in the raw .state and then heat-treated :aat 1350ifor. 34 hours t'intsteam;

71b.) .The .obtained pellets were treated :with dilute sodium hydroxide.solution, washed, and then. treated with :aluminum sulfate .isolution:as. in .112 above. The pellets were ;finally. calcined .at.1050 F.'for:2 hours .in "air.

In this instance the "raw Tka'olin \was "brought to high activity levelwithout .zpreliminary' acid treatment as will be noted from thefollowing'srev sults obtained by the fCAT-sA method:

Catalyst Gasoline Coke Gas Grav.

IIIa Raw clay pellets heat 5 I f treated 9 .l..l 2. 8 1. 3 IIIb PeIIetsfrom' II-Ia treated with NaOH A1 salt. 31. 2 3. 2 7. 4 1 35 Although inthe preferred embodiment aluminum salts are employed to activate theclay, it is within the scope of the present invention in the preparationof contact masses for use as catalysts, to employ salts of other metalsthe oxides of which form catalytically active combinations with silica,such as salts of magnesium, zirconium or beryllium.

Obviously many modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof and therefore only such limitations should be imposed asare indicated in the appended claims.

I claim as my invention:

1. The method of producing active contact masses from kaolin claynormally yielding masses of low activity by acid-treatment whichcomprises subjecting the clay to heat-treatment at a temperature above500 F., contacting the heat-treated clay with a dilute solution of analkaline hydroxide, washing the alkali treated clay with water andthereafter replacing incorporated alkali metal in the'clay with aluminumby treatment with a solution of an aluminum salt.

2. The method of producing active contact masses from a kaolin claywhich comprises subjecting raw kaolin to treatment with mineral acid,forming the kaolin into pellets, subjecting the pellets to calcinationat a temperature above 500 F., treating the calcined pellets with dilutesodium hydroxide solution, washing and drying the treatedpelletsand'thereafter contacting the pellets with an aluminum salt solution.

3. The method of producing contact masses of high activity from a kaolinclay which comprises subjecting raw kaolin to treatment with mineralacid at elevated temperature for a time sufiicient to increase theactivity of the kaolin, purifyingthe acid-treated kaolin by removingadhering acid and Water soluble substances, drying and shaping thepurified kaolin to form pellets, subjecting the formed pellets to heattreatment at a temperature above 500 F., soaking the heattreated pelletsin dilute aqueous sodium hydroxide to incorporate a substantial quantityof sodium in the pellets without substantial disintegration of thepellets, washing the thus treated pellets in water, replacing theincorporated so dium in the pellets with aluminum by treatment with analuminum salt solution, washing the pellets to remove soluble anions,drying and calcining the washed pellets.

4. The method of preparing an active catalyst from kaolin whichcomprises subjecting raw'kaolin to treatment with mineral acid atelevated temperature to an extent suflicient to increase the catalyticactivity of the kaolin, ex-

trudinfgthe acid-treated kaolin to form pellets,

calcining-'fthe pellets at a temperature above 500 F.. incorporatingsodium hydroxide in the formed pellets, Washing and drying the,pellets,v and treating the dried pellets with an aluminum salt The.following references are of record in the tile of this patent:

5 STATES PATENTS Number 9 Name Date 2,066,212 McKellar Dec. 29, 1936Number a I Name Date Tropsch June 11, 194% Thomas et a1. Jan. 21, 1941,

Lee et a1 July 14,1942; Ruthruff June 1, 1943 Ruthruff July 6, 1943Ruthruff Jan.;2-';- 1945, Veltman Apr. 24, 1945 Heidelberg et a1. 1--..Oct. 30. 1945 Richardson Apr. 2', 1946 Pierce et a1. July 9- 1946Garrison et a1 Sept. 24, 1946 Ewing .Nov. 5, 1946 Gray Jan. 21, 1947Oulton Mayi4,'1948 Shabaker et a1. Apr. 5,1949 Bodkin et a1 Aug. 30,1949

2. THE METHOD OF PRODUCING ACTIVE CONTACT MASSES FROM A KAOLIN CLAYWHICH COMPRISES SUBJECTING RAW KAOLIN TO TREATMENT WITH MINERAL ACID,FORMING THE KAOLIN INTO PELLETS, SUBJECTING THE PELLETS TO CALCINATIONAT A TEMPERATURE ABOVE 500* F., TREATING THE CALCINED PELLETS WITHDILUTE SODIUM HYDROXIDE SOLUTION, WASHING AND DRYING THE TREATED PELLETSAND THEREAFTER CONTACTING THE PELLETS WITH AN ALUMINUM SALT SOLUTION.